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serve our attention. I think that it is sufficient to describe seven; 

 1. The occipito-mental, five inches in length, extending from the 

 most projecting part of the occiput to the point of the chin, also 

 called the great or oblique diameter, and which M. Flamant de- 

 nominates the sur-occipito-mental ; 2. The occipito-frontal, about 

 four inches long, which extends from the occipital protuberance to 

 the forehead, and which is also called the straight or antero-posterior 

 diameter; 3. The bi-parietal, or transverse diameter, reaching from 

 one parietal protuberance to the other, and which is three inches and 

 a half ; 4. The bi-temporcd, or smallest diameter, measured from the 

 root of one zygomatic apophysis to the opposite one, and whose 

 length is two inches and a half; 5. The vertical or trachelo-breg- 

 matic, which passes through the head perpendicularly, descending 

 from the vertex to the anterior part of the occipital foramen, and is 

 about three inches and a half; 6. The fronto-rnental, or facial, whose 

 name sufficiently indicates its situation, and whose extent is three 

 inches; 7. Finally, the occipito-bregmatic, the most important of all, 

 whose posterior extremity is situated between the occipital protube- 

 rance and foramen magnum, and proceeds to terminate at the anterior 

 fontanelle; its length is nearly three inches and three quarters. 



522. Circumferences. These various diameters are accompanied 

 with an equal number of circumferences, which should receive the 

 same names, and whose lengths are equally various: 1. The occipito- 

 mental or great circumference, which divides the head into two late- 

 ral halves exactly similar to each other, passes at the same time over 

 both extremities of the occipito-mental diameter, and which, when 

 multiplied by three, equals the length of the circumference, and also 

 over those of the fronto-mental, occipito-frontal, vertical, and occipito- 

 bregmatic; 2. The facial circumference, which passes over the fore- 

 head, the chin, and the cheeks; 3. The circumference of the vertical 

 diameter, which passes a little in front of the parietal protuberances, 

 and thus divides the head transversely; 4. That of the occipitofron- 

 tal diameter, which at the same time embraces the extremes of the 

 transverse diameter, and separates, horizontally, the vault from the 

 base of the cranium; 5. That of the occipito-bregmatic axis, which 

 is also the special circumference of the bi-parietal diameter, and the 

 most important of all, for in all natural labors it is found in relation 

 with the circle of the pelvic straits; 6, Finally, the circumference of 

 the bi-temporal or smallest diameter should pass also over both ends 

 of the vertical or occipito-bregmatic; its existence ought not to be ad- 

 mitted except in the greatest possible degree of reduction of the head; 

 a knowledge of it then becomes of the highest practical interest, for 

 by comparing its line of tension, that is to say, its bi-teraporal axis 



